Campimetry is the study of the visual field for the detection of defects thereof (such as scotomas or areas with partial or total loss of vision) by means of an instrument called campimeter or perimeter. The visual field is defined as the space wherein an object may be seen whilst the eyes of the person under study are fixed forward.
There are different methods for studying the visual field; depending on the type of technique or perimeter used and the information obtained from them, perimetry may be classified into:                Qualitative campimetry: amongst them, the most widely used is confrontation perimetry: a basic, simple technique performed by the professionals themselves without the need for specific equipment (perimeter) which only provides basic information as to whether or not there is a visual field defect. It is used as a screening test.        Quantitative campimetry: It uses more complex techniques that require specific equipment (perimeter); amongst them, the most widely used are kinetic perimetry, manual or computerised (wherein the perimeter emits moving luminous stimuli, all at the same intensity) and static perimetry, manual or computerised (wherein the perimeter emits stationary luminous stimuli at different intensities and different locations); depending on the number and the location of the luminous stimuli that the patients recognise, or fail to, visual field maps are drawn which make it possible to identify non-seeing areas or areas with abnormal visual sensitivity (scotomas), and to exactly determine the size, the location and the depth of the scotoma area.        
In confrontation perimetry, the patients remain seated in front of the examiner. Both eyes are examined independently; to do so, the patients must close one eye and stare at the examiner's opposite eye whilst the latter asks them to indicate when they see and/or cease to see an object that moves between both of them, throughout the visual field of the examined eye. Subsequently, the same operation is repeated with the fellow eye.
In kinetic perimetry, the patients remain seated in front of the perimeter. Both eyes are examined independently; to do so, the patients must close one eye whilst the examiner asks them to indicate when they see and when they cease to see a luminous beam that moves throughout the visual field of the eye under study. Subsequently, the same operation is repeated with the fellow eye.
In static perimetry, the patients remain seated in front of the perimeter and both eyes are examined independently; to do so, the patients must close one eye whilst the examiner asks them to indicate when they see a flashing luminous beam, at different intensities, that appears in different areas of the visual field of the eye under study. Subsequently, the same operation is repeated with the fellow eye. The most habitual way to examine the visual field is to determine the weakest luminous stimulus that the eye is able to perceive in each region, when presented over a uniformly illuminated background (differential luminous threshold).
In order to estimate the normality or abnormality of the result, the instrument usually has age-adjusted normative reference values from the normal population, examined in the same manner. The examination result is shown as absolute differential sensitivity values on a logarithmic scale (decibels) or as the difference between these values and the reference values (deviations or defects). Two of the most prestigious indices used to indicate the condition of the visual field are the mean defect or deviation of the points examined, measured as a mean (MD), and the irregularity, measured as the variance or standard deviation of the local defects or deviations (Pattern Standard Deviation, PSD, or Loss Variance, LV).
However, the fact that subjects present values that are distant from the habitual mean values does not guarantee that they are abnormal. For example, a subject may have an extremely low or high value with respect to a reference population and still be normal. Moreover, the fact that subjects fall within the habitual mean values does not guarantee that they are normal. For example, a subject may have a normal weight and have suffered an abnormal weight loss. Our experience indicates that, in these cases, harmony can be an excellent indicator of normality.
On the other hand, it is well-known that keeping the eye observing a uniformly illuminated surface during the examination, without any other contrast phenomena than those of the examination stimulus, is contrary to the physiology of vision, wherein changes in contrast are necessary in order to “refresh” the functioning of the retina. This produces a progressive reduction in sensitivity, which we call “fatigue effect”, to refer to a fatigue of the neurological mechanisms of vision, which distorts the patients' actual functional capacity. In order to reduce this undesired phenomenon, our system periodically presents a rapid sequence of figures with random contrasts and shapes, in the form of short flashes interspersed between the examination periods.